Hi Anna,

Isn't it exciting when you get a good bloom on all those summer plants? But once the blooms fade, it's hard to keep track of what to do for each specific type of plant. Below is some information that I hope will help:

Lavender: Deadheading lavender is good, can lead to some reblooming, and should happen right after the first round of blooms are spent (no more color showing on the flower heads). Snip the flower stalks low enough so that they are hidden in the leaves, but don't cut down to the woody stems. Leave some green growing tissue on the stem. There is a nice diagram of the right place to trim at https://ucanr.edu/sites/EDC_Master_Gardeners/files/168086.pdf. Information on lavender is also available at http://www.gardening.cornell.edu/homegardening/scene9108.html.

Hostas: Some people cut off the flowers before they mature so that they can better enjoy the foliage. If you like the flowers, then deadhead them after they have passed by cutting the flower stalk down to the crown of the plant. See more information at https://extension.umn.edu/flowers/hostas.

Bee balm: Deadheading will keep your bee balm blooming longer. Just cut back the flowering stems when blooms have gone by to within 1/4-inch of a leaf or leaf bud near the top of the stem to encourage the plant to produce new flowers. More about bee balm at http://www.gardening.cornell.edu/homegardening/scene13fe.html.

Cosmos: Cutting off spent flowerheads allows the plant to put its energy into the next buds, but it also removes the seeds, so if you are hoping for the plants to reseed themselves you have to let those "dead" flowers go to seed. If you just want to keep them looking good, prune off spent flowers right away. More info is at https://extension.sdstate.edu/enjoy-more-flowers-your-garden-deadheading-regularly and https://plants.ces.ncsu.edu/plants/cosmos/.

Hydrangeas: You can remove spent flowers from hydrangeas once they have gone by and look dry/change color. Some hydrangea blooms (such as oak leaf variety) look great when they are dry, and you can leave them on the plant for fall and winter interest. If you need to cut any stems or branches, though, you have to be careful about timing. You didn't mention what type of hydrangeas you are growing and that makes a big difference as to when and how you prune them. Fortunately, there are good resources that will guide you for either type, such as https://ucanr.edu/datastoreFiles/268-86.pdf and https://chesapeake.ext.vt.edu/content/dam/chesapeake_ext_vt_edu/files/pruning-hydrangeas.pdf.

I hope this information is helpful, and please don't hesitate to contact us if you have more questions. Enjoy all those great blooms!

Best,